Any ideas for getting a Busa below 100 db without losing power?
I have a Busa in the back of my mini with a pipercross air filter fitted and a Remus sports bike can with a removeable baffle.
Had it noise tested at 7150 Rpm 110db
Witht he baffle in it dropped to 108db but its still to loud for most trackdays so i really need to get it below 100 to be safe.
Some people have suggested that i change the air filter as it may be induction noise but i dont want to loose power really and refit the std airbox, but ido have the room to construct a decent exhaust system in the back.


Z-cars had to run 2 cans in line to run at oulton but it looks a bit gash to me........


I thought of doing this.........



Has anyone got any proven ideas or recommend a good silencer to do the job?

Cheers

What about a standard pair of 'Busa silencers? Make a y-piece and wedge them under there somehow - you can afford top lose a horsepower or two!

p.s. Your Mini is a beaut!

[Edited on 5/10/06 by Coose]

There really is no substitute but to restrict those gases, either at the induction or exhaust ends. Try using the original can this should get you down to below 100Db. Obviously it will hold you back with your power but you don't have much alternative...

Steve

If you're failing on the static test, an airbox won't make that much difference as you get most induction noise when the engine is under load.

A race can will always be bloody noisy though, the only effective way is either restriction or sheer volume of silencer, ie a bloomin great big 7 x 30" can or similar.

I swapped a 24" x 5" silencer for a 28" x 6" can and lost a few decibels. A bigger one would lose a little more.

A well designed airbox shouldn't lose much / any power. If the diameter of the inlet to the box is bigger than the venturi / throttle body then it will be less restrictive than the throttle body.

What silencers is everyone else using??
Ive got a std busa can on the way but i know they are very restrictive!!!
It looks very subtle at the moment (till you hear it passing you)so dont want to loose that aspect


What do the radicals etc use?
probably something expensive!!!


cheers

[Edited on 5/10/06 by markrally73]

I'd suspect that very few people that do trackdays run race cans like yours unless they stick to specific circuits who don't care about noise, most will either run restrictive stock cans (the R1 can is popular) or big fat custom made straight through cans from various sources.

From when I spoke to simpsons about noise when I had my exhaust built and from paul907's research the general rule of thumb seems to be that the longer the silencer the less decibels, the wider diameter the less frequently it'll need repacking. Surely having two silencers in series as long as the diameter of the through pipe remains the same that shouldn't affect the power much at all?

Ned.

Just fited a stock Hayabusa can as it was a direct replacement / fit for the remus can which was fitted already and it dont sound any quieter really but i havnt had it noise tested yet to get an exact reading.
Can you buy a 7 x 30 Round silencer off the shelf or is it a custom made jobby?

Cheers

Nice car, looks like you've got room for one of these:-




It's a standard silencer system from an Elise / MGF I think. Should be nice and quiet, and they are quite cheap too, as most people upgrade them so there are quite a few originals on ebay.

HTH

Mike

ELise silencer will be tuned for the wrong frequencies for a Busa..

Bes bet is to get a Quill Powerflow T3 can, this is a road legal can, and if you get the zx12r version you will probably find it will flow enough gas for the Busa (which stock has 2 cans) and get it well under 100db...

It also gives more power than a stock muffler, and a better, deeper sound..

quote:

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Originally posted by G.Man
ELise silencer will be tuned for the wrong frequencies for a Busa..

Bes bet is to get a Quill Powerflow T3 can, this is a road legal can, and if you get the zx12r version you will probably find it will flow enough gas for the Busa (which stock has 2 cans) and get it well under 100db...

It also gives more

power than a stock muffler, and a better, deeper sound..

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No, as the ZX12 only has a single larger can and produces the same power as the busa, you can assume the single can will flow approx the same as 2 smaller busa cans

quote:

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Originally posted by markrally73
Can you buy a 7 x 30 Round silencer off the shelf or is it a custom made jobby?
Cheers

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IIRC when wscc did a group buy and when I got mine the 7"x [as long as they could make it] 28-29" was in the region of £275 if this helps. That was from simpsons, not the cheapest but highly recommended, were relatively local and did a superb job of mine.

Ned

Had a quote off BTB exhausts who do the systems for powertec and radicals etc (well known for busa engines) They reckon on £550 + Vat to sort the job out!!!
They also commented that i may have a problem with induction noise aswell and i must address this first before i took the car to them.
Ie I would need to make an enclosed airbox and have it fed by a 3"tube with a remote filter ie Cone filter. as this will lower the induction noise.
The REMUS can i have at the moment is a road legal can for a 1200 bandit which has a removeable baffle so i dont think that a quill can will do any better? well i aint going to risk spendin hundreds for it not to work???

Cheers

Ps i will look into simpsons exhausts.

I bought one of the group buy Simpson cans that Ned mentioned, and for £230 its extremely well made, although as Ned says, as a one off purchase they are nearer £250-275.

If BTB want to charge you £500+ just for a silencer I'd tell them where to go, if its for a complete system though then the price is reasonable. Im still not sure their work is up to Simpson standards though, a Mustang that my uncle preps had an exhaust system done by BTB I think, it was bloomin expensive but not as nicely fabricated as either my Simpson can or my Promotive manifold.

Chris

[Edited on 9/10/06 by ChrisGamlin]

£550 + Vat was a rough figure over the phone for a system to connect to my downpipes made to suit my car as they are familiar with the z-cars kit and layout etc but obviously.
Wil do a google search for simpsons and call them tomorrow

Cheers

quote:

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Originally posted by markrally73
Had a quote off BTB exhausts who do the systems for powertec and radicals etc (well known for busa engines) They reckon on £550 + Vat to sort the job out!!!
They also commented that i may have a problem with induction noise aswell and i must address this first before i took the car to them.
Ie I would need to make an enclosed airbox and have it fed by a 3"tube with a remote filter ie Cone filter. as this will lower the induction noise.
The REMUS can i have at the moment is a road legal can for a 1200 bandit which has a removeable baffle so i dont think that a quill can will do any better? well i aint going to risk spendin hundreds for it not to work???

Cheers

Ps i will look into simpsons exhausts.

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